If you're ever in my (gravel) driveway, you may get lucky and find mine. Since I couldn't, and couldn't find replacements and needed to leave on a trip, I drove machine screws in (couldn't really match the thread, but these work), so now I have to use a screwdriver to open the vent panel.
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.